Project description:To identify the disparaties of D^b-nucleoprotein specific resident memory CD8 T cells between young and aged mice, we pooled n=11 aged or n=18 young lungs together after intraveounously labeling T cells and sorted ivCD90- CD8a+ CD44hi CD69+ D^b-NP tetramer (PE+ & APC+) cells. By scRNA-seq, we found the aged population was missing a cluster in the young population that resembled typical functional resident memory CD8 T cells indicating that aged resident memory CD8 T cells of this specificity would have poor recall function.
Project description:Skeletal muscle dysfunction in survivors of pneumonia is a major cause of lasting morbidity that disproportionately affects older individuals. We found that skeletal muscle recovery was impaired in aged compared with young mice after influenza A virus-induced pneumonia. In young mice, recovery of muscle loss was associated with expansion of tissue-resident skeletal muscle macrophages and downregulation of MHC II expression, followed by a proliferation of muscle satellite cells. These findings were absent in aged mice and in mice deficient in Cx3cr1. Transcriptomic profiling of tissue-resident skeletal muscle macrophages from aged compared with young mice showed downregulation of pathways associated with phagocytosis and proteostasis, and persistent upregulation of inflammatory pathways. Consistently, skeletal muscle macrophages from aged mice failed to downregulate MHCII expression during recovery from influenza A virus induced pneumonia and showed impaired phagocytic function in vitro. Like aged animals, mice deficient in the phagocytic receptor Mertk showed no macrophage expansion, MHCII downregulation or satellite cell proliferation and failed to recover skeletal muscle function after influenza A pneumonia. Our data suggest that a loss of phagocytic function in a CX3CR1+ tissue-resident skeletal muscle macrophage population in aged mice precludes satellite cell proliferation and recovery of skeletal muscle function after influenza A pneumonia.
Project description:Aging is known to alter the host repsonse to influenza infection. Here, we use single-cell RNA sequencing (scRNA-seq) to identify cellular changes in the lungs of young (16-week-old) and aged (80-week-old) mice following influenza infection.
Project description:Aging is known to alter the host repsonse to influenza infection. Here, we use 10x Visium spatial sequencing to identify spatial changes in mRNA expression of left lungs of young (16-week-old) and aged (80-week-old) mice following influenza infection.
Project description:Aging is known to alter the host repsonse to influenza infection. Here, we use bulk RNA sequencing (bulk RNA-seq) to identify cellular changes in the lungs of young (16-week-old) and aged (80-week-old) mice following influenza infection.
Project description:Aging is known to alter the host repsonse to influenza infection. Here, we use bulk RNA sequencing (bulk RNA-seq) to identify cellular changes in the livers of young (16-week-old) and aged (80-week-old) mice following influenza infection.
Project description:To identify molecular characteristics of young and aged lungs post-influenza infection, we isolated RNA from lungs 60 days post-infection and examined by bulk RNAseq. We found a large number of genes remain upregulated in aged compared to young lungs. Comparison with expression of immune system-related genes from Nanostring expriments indicated this was largely infection-induced rather than baseline differences between age. This indicates that aged lungs fail to return to homeostasis following a viral respiratory infection
Project description:Aging is a major risk factor for host morbidity and mortality upon acute respiratory virus infections. To better elucidate the immune determinants of viral pathogenesis during aging, we conducted a time-course single-cell RNA sequencing (scRNAseq) and high-dimensional flow cytometry analysis on the pulmonary responses against influenza infection in young or aged mice. Notably, aged mice exhibited decreased populations of alveolar macrophages (AMs) and dendritic cells (DCs), alongside an increase in monocyte-derived macrophages (MoMs) and interstitial macrophages (IMs), which last weeks after acute viral infection. Additionally, there was enhanced accumulation of respiratory adaptive immune cell cells including tissue resident helper CD4 T cells (TRHs), CD8 tissue resident memory cells (TRMs) and a unique B cell population resembling age-associated B cells. Gene set enrichment analysis (GSEA) comparing lung transcriptomes of young and aged mice across time points highlighted persistent type I and type interferon signaling in aged hosts, especially in the macrophage population. Interestingly, inhibiting interferon signaling in aged mice after viral clearance led to ameliorated long-term sequelae, along with a decrease in IM and TRH populations. Our findings suggest that IFNα/γ signaling, particularly in MoM/IM, is pivotal in the development of long-term sequelae following acute respiratory infections in aged hosts.